This invention relates to improved reliably low-resistance electro-mechanical switches and more particularly to snap action, chatter-free switches of compact, durable, low-cost construction adapted for direct incorporation in or as a part of printed circuit devices or in other installations. The invention is herein illustratively described by reference to the presently preferred embodiments thereof; however, it will be recognized that certain modifications and changes therein with respect to details may be made without departing from the essential features involved.
In order to achieve positive instantaneous low-resistance steady state switching action in a snap-action switch it is desirable not only that the switch contactor snap abruptly into and from switch-actuated position but that the contact engagement that it makes remain electrically stable and of low electrical resistance from the instant of such engagement forward. However, the very abruptness of contactor movement in closing or actuating such switches can introduce circuit noise and electrical transient effects due to the bounce or chatter of the mechanical part as in changes positions. It is a broad object of this invention to overcome this difficulty and more particularly to do so in a switch of simple, compact form and one that affords a positive snap-action tactile sensation when actuated.
A further object hereof is to provide such a switch of low-cost construction having unusually low electrical resistance achieved upon and after the instant of actuation and achieved despite mechanical transients in the moveable contactor of the switch.
Berry, U.S. Pat No. 3,735,058 dated May 22, 1973, discloses a toroidal spring contactor type switch in some respects resembling the present invention but lacking the important essentials of the same. In that prior art device an objective is to avoid snap action in closing the switch contacts, and the longitudinal discontinuity in the guide post surface is to satisfy a switch-open detent requirement.